The long term goals of this research are to understand the structural basis of the large non-receptor protein tyrosine kinase from the Abelson gene, Ab1. We wish to understand the nature of its interactions with extra-Ab1 ligands, and the possible intra-Ab1 interactions among the several protein domains. Concentrating on possible structural correlates of the transforming potential of Ab1, a protooncogene product, the structure and dynamics, studied by high resolution NMR, of ligated domains of the SH2 and SH3 of Ab1, and a combined construct,SH(3/2) will be determined. Ab1 itself may use other SH2 and SH3 containing proteins to modify its activities in signal transducing particles, in its possibly multiple roles. Based on the identification of sites for other SH3's to bind to Ab1, peptide ligands have been made imitating these segments and the structure and dynamics of these segments bound to non-Ab1 SH3's will be determined.